Late in the decade, Zerbe began in features with a role in the prison drama, "Cool Hand Luke" (1967). His assertive, often gritty manner suited him for tough adventure films like "Papillon" (1973, as the leper colony chief), Westerns like "Rooster Cogburn" (1975), and detective dramas including "They Call Me MISTER Tibbs!" (1970) and the film noir "Farewell My Lovely" (1975). TV-movie work, meanwhile, began with the second pilot movie for the "Ironside" series, "The Priest Killer" (1971). Soon thereafter, he acted in his first series, the mature and low-key, if sometimes formulaic, detective series "Harry O" (1974-76), starring David Janssen. For his sympathetic but street-smart Los Angeles police lieutenant who maintains ties with the cop-turned-PI hero, Zerbe won a supporting actor Emmy in 1976. After appearing in many prestigious miniseries including "Centennial" (1978), "A.D." (1985) and "Dream West" (1986), and TV-movies such as "The Seduction of Miss Leona" (1980, which gave him a rare romantic lead), Zerbe played the leathery Teaspoon Hunter in another series, "The Young Riders" (1989-92).
Feature work also continued for Zerbe in films including "First Deadly Sin" (1980), "The Dead Zone" (1983), and his portrayal of particularly nasty and parasitic marine biologist in the James Bond thriller "License to Kill" (1989), but petered out at the end of the decade. Along with TV work, Zerbe has worked consistently on the stage. His sharp features and charismatic line readings have suited him for roles ranging from the scheming, duplicitous Iago of "Othello" to the flamboyant, theatrical "Cyrano de Bergerac". He had ongoing associations with the Mark Taper Forum from the late 60s, and the Seattle Repertory Company from the mid-70s. Zerbe also occasionally performed his one-man evening of poetry by e e cummings, "It's All Done with Mirrors", and his two-man poetry show with Roscoe Lee Browne, "Behind the Broken Words". In 1990, he began a stay with the GeVa Theater in Rochester, New York as associate artistic director.